Managing flow in a conduit by means of a valve allows establishing different degrees of conduit closure, from completely closed to completely open. This variation in the degree of closure depends on the angle adopted by the valve plug such that the plug restricts the passage to a greater or lesser extent.
There are circumstances in which the maximum degree of closure, the maximum degree of opening, or both, must be limited. This is the case when there is a need to assure minimum flow through the conduit at all times, minimum opening situation; or to assure a minimum pressure drop, maximum opening situation, for example.
This maximum degree of closure or opening can be established by means of fixed stops suitably located in a position inside the conduit, being interposed in the plug trajectory. Given that the plug mechanically interferes with the stop, the range of angular movement of the plug is thus limited by the limit position established by the stop.
The stop which moves integrally with the plug can be regulated by means of a screw. Screwing or unscrewing this screw modifies the position of the stop and therefore the position of the maximum degree of opening or closure. One way to carry out such maximum regulation consists of the screw itself acting as a stop. In this case the screwing or unscrewing linearly moves the position of the end of the screw and therefore the position in which the plug abuts. Such regulation is difficult and above all very limited angle-wise. Additionally, when the threaded element is in contact with the flow in the conduit the probability of its operation being affected by dirt is very high.
The present invention provides an opening or closure limiting device suitable for valves allowing a manual, quick and very mechanically safe regulation. Furthermore, this limitation does not prevent the use of additional limitations in the opening or closure such as limitations imposed by the actuator moving the plug.